DE2706128A1 - FAST CRYSTALLIZING POLYESTER COMPOUNDS - Google Patents

Description

5090 Leverkusen, Bayerwerk Pv / AB

Rapidly crystallizing polyester masses

The present invention relates to highly crystalline, rapidly crystallizing thermoplastic compositions made from a high molecular weight polyalkylene terephthalate and a phthalic acid ester.

Polyalkylene terephthalates have gained considerable importance as raw materials for the production of fibers, films and moldings. Due to their partially crystalline structure, they have excellent properties, such as high wear resistance, favorable creep behavior and high dimensional accuracy, and are therefore particularly well suited for the production of mechanically and thermally highly stressed molded parts. An additional improvement in the mechanical properties can be achieved by incorporating reinforcing materials, for example glass fibers (GB-PS 1,111,012, US-PS 3,368,995, DT-AS 2,042,447 ).

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Due to its special physical properties, polyethylene terephthalate (PÄT) is particularly suitable for Manufacture of fiber products and foils, but hardly for injection molding because of the high mold temperatures (around 140 C) and relatively long pressing times are required. This serious disadvantage prevents the use of injection molding from Polyethylene terephthalate is almost perfect despite its high rigidity and heat resistance.

Polypropylene terephthalate (PPT) and polybutylene terephthalate (PBT) require because of their higher rate of crystallization although shorter press times and lower Formte'mperaturen however (about 8O ⁰ C) 'possess physical properties compared to polyethylene terephthalate worse, especially a lower Härmestandfestigkeit.

Efforts have been made to create polycondensates which combine the good properties of both polyethylene terephthalate and polypropylene or polybutylene terephthalate. For example, it is known that the tendency of polyethylene terephthalate to crystallize can be improved by nucleation with finely divided, solid inorganic substances (NL-PS 6 511 744).

High crystallinity ensures hardness, dimensional stability and dimensional stability even at higher temperatures. This high crystallinity should be achieved as quickly as possible so that an optimal level of properties is obtained. In addition, the injection cycle depends on the mold service life, the length of which determines the cost-effectiveness of the process *. These cycles are too long even at high mold temperatures and therefore make it more difficult for polyethylene terephthalate to penetrate

in the production of moldings by injection molding.

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In addition, it has long been an intimate concern of polyester manufacturers, as well as other polyalkylene terephthalates with increased crystallization rate and higher crystallinity.

It has now surprisingly been found that polyalkylene terephthalates then have higher crystallinity and greater crystallization rate if they are 0.5% by weight of a phthalic acid ester.

The present invention makes it possible to achieve the degree of crystallinity required for high dimensional stability to be achieved more quickly and thus to process the polyester compounds with greatly reduced injection cycles. A Another advantage of the polyester compositions according to the invention is the lowering of the mold temperature without the good crystallization behavior is impaired. The injection molding compound cools down faster, which the mold life is also shortened.

The invention relates to highly crystalline, rapidly crystallizing thermoplastic compositions consisting of

a) 70 - 99.5, preferably 85 - 99.5 wt. t of a high molecular weight polyalkylene terephthalate with an intrinsic viscosity of at least 0.6 dl / g, preferably at least 0.8 dl / g (eaten al * 0, 5% by weight solution in a phenol / tetrachloroethane mixture in a weight ratio of

1 ti at 25 ° C) and

b) 0.5-3O, preferably 0.5-15, parts by weight of a phthalic acid ester with an average molecular weight of 200 to 20OO of the formula

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O O

Il Il

R ¹

wherein

R is a branched aliphatic radical with 1-12 C atoms,

2 3 R, R is a linear or branched aliphatic radical with 1 -12 carbon atoms,

η O or an integer from 1 to 4 and χ O or an integer from 1 to 15 are.

The average molecular weight of the phthalic acid ester b) is if it is a mixture of oligomers, measured by vapor pressure osmometry in acetone.

Another object of the present invention is a process for the production of highly crystalline, rapidly crystallizing thermoplastic compositions, characterized in that 70 - 99.5, preferably 85 - 99.5 " T of a high molecular weight polyalkylene terephthalate with an intrinsic viscosity of at least 0.6 dl / g, preferably at least 0.8 dl / g. (measured as 0.5% by weight Solution in a phenol / tetrachloroethane mixture in a weight ratio of 1: 1 at 25 ° C) and 0.5-3O, preferably 0.5-15% by weight of a phthalic acid ester of the above Constitution atlscnt and homogenized in the melt. Of the Process can see B. take place in a mixing screw; the solidified melt can then be granulated.

Bin further the subject of the present invention is Use of phthalic acid esters of the above constitution to increase the crystallization and the rate of crystallization of polyalkylene terephthalate ^.

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The dicarboxylic acid component of the polyalkylene terephthalate a) consists of terephthalic acid, which is up to 10 mol%, based on the acid component, through other aromatic dicarboxylic acids with 6-14 carbon atoms, through aliphatic ones Dicarboxylic acids with 4-8 carbon atoms or replaced by cycloaliphatic dicarboxylic acids with 8-12 carbon atoms Examples of such dicarboxylic acids are phthalic acid, isophthalic acid, naphthalene-2,6-dicarboxylic acid, Diphenyl-4,4'-dicarboxylic acid, adipic acid, sebacic acid and Called cyclohexanediacetic acid.

The diol component of the polyalkylene terephthalate, which consists of 1,3-propanediol, 1,4-butanediol, 1,5-pentadiol, 1,6-hexanediol or 1,4-cyclohexanedimethanol, but preferably ethylene glycol, can be up to 10 mol% by other aliphatic Diols with 3-8 carbon atoms, cycloaliphatic diols with 6-15 carbon atoms or aromatic diols with 6-21 carbon atoms be replaced. Examples of suitable diols are 3-methylpentanediol-2,4, 2-methylpentanediol-1,4, 2,2,4-trimethylpentanediol-1,3, 2-ethylhexanediol-1,3, 2,2-diethylpropanediol-1, 3, hexanediol-1,3, 1,4-di (B-hydroxy-ethoxy) benzene, 2,2-bis (4-hydroxycycIohexyl) propane, 2,4-dihydroxy-1,1,3,3-tetramethylcyclobutane, 2,2-bis (3-ß-hydroxyethoxyphenyl) propane, 2,2-bis ( 4-hydroxypropoxy-phenyl) propane are listed.

Of course, the polyalkylene terephthalates a)

by tri- or tetravalent alcohols or tri- or tetrasic acids are branched, as described, for example, in DT-OS 1 900 270 (* US-PS 3,692,744) is. Suitable branching agents are e.g. trimesic acid, pyroroellitic acid, trimethylolpropane and -ethane, Pentaerythritol. It is advisable not to use more than 1 mol%, based on the acid component, of branching agent to use.

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The polyalkylene terephthalates can be prepared in a manner known per se by

a) terephthalic acid and / or the corresponding dialkyl terephthalates, preferably the Oimethylester, with 1.05 to 5.0, preferably 1.4-3.6, Hol of the diols, based on 1 mole of dicarboxylic acid component, and optionally the branching agent in the presence of esterification and / or transesterification catalysts esterified or transesterified and

b) the reaction products thus obtained in the presence of polycondensation catalysts polycondensed between 200 and 320 C under reduced pressure (^. 1 Torr).

Both the first (a) and the second (b) step of the condensation are carried out in the presence of catalysts, as described, for example, by RE WiIfong in J. Polym. May be. 5Λ, 385 (1961) are described. Some of these catalysts are more effective accelerators for the esterification reaction (A), others for the polycondensation (B), while still others are quite effective catalysts for both (C).

The catalysts which are suitable for accelerating the 1st reaction stage (A) include

1. Lithium, sodium, potassium, calcium, strontium, boron as Metals, oxides, hydrides, formates, acetates, alcoholates or glycolates;

2. Calcium and strontium chlorides and bromides

3. tertiary amines;

4. Calcium and strontium malonates, adipates, benzoates, etc .;

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5. Lithium salts of dithiocarbamic acids.

Suitable for catalysis of the polycondensation step a Catalysts (B) are e.g.

1. Molybdenum, germanium, lead, tin, antimony as metals, oxides, hydrides, formates, alcoholates or glycolates;

2. zinc and lead perborates and borates;

3. Zinc, manganese (II), cobalt, magnesium, chromium, iron and cadmium succinates, butyrates, adipates or enolates of a diketone;

4. zinc chloride and bromide;

5. Lanthanum dioxide and titanate;

6. neodymium chloride;

7. common salts of antimony, such as potassium antimony tartrate, and salts of antimony murs such as potassium pyroantimonate;

8. zinc or manganese salts of dithiocarbamide-S-acids;

9. cobalt naphthenate;

10. Titanium tetrafluoride or tetrachloride j

11. Alkyl orthotitanates »

12. titanium tetrachloride ether coraplexes;

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13. Quaternary ammonium salts containing a titanium hexaalkoxy radical wear; Titanium tetraalkoxides, alkali or alkaline earth metal compounds of aluminum, zirconium, or titanium alkoxides;

14.Organic quaternary ammonium, sulfonium, phosphonium and oxonium hydroxides and salts;

15. Barium malonate, adipate, benzoate etc.

16. Lead, zinc, cadmium or manganese salts of the monoalkyl ester a phenylenedicarboxylic acid;

17 ". Antimony-catechin complexes with an amino alcohol or with an amine and an alcohol;

18. Uranium trioxide, tetrahalide, nitrate, sulfate, acetate.

Suitable catalysts to accelerate both reaction steps C are e.g.

1.barium, magnesium, zinc, cadmium, aluminum, manganese, Cobalt as metals, oxides, hydrides, formates, alcoholates, glycolates, preferably acetates;

2. aluminum chloride and bromide;

3. Zinc, manganese (II), cobalt, magnesium, chromium, iron and cadmium succinates, butyrates, adipates or enolates of a diketone.

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The compounds most suitable as catalysts A are Ca-, Zn-, Mn salts, in particular as acetates.

The most suitable catalysts B are the compounds of zinc, manganese, cobalt, antimony, germanium, titanium and Tin, such as B. zinc and manganese acetate, antimony trioxide, trichloride, triacetate, germanium dioxide and tetrachloride.

The most suitable catalysts C are in particular titanium compounds such as. B. Tetraalkyltitansäureester with alkyl groups with 1-10 C-atoms, like Tetraisopropyltitanat and Tetrabutyl titanate.

The catalysts are used in amounts of from 0.001 to 0.2% by weight, based on the dicarboxylic acid component.

Thereafter, inhibitors can be added to inhibit the catalysts after completion of the 1st reaction step and to increase the stability of the end product, such as are e.g. at H. Ludewig, polyester fibers, 2nd edition, Akademie-Verlag, Berlin 1974 are described. Examples of such inhibitors are phosphoric acid, phosphorous acid and their aliphatic, aromatic or araliphatic esters, e.g. alkyl esters with 6 to 18 carbon atoms in the alcohol component, phenyl esters, their phenyl radicals optionally with 1-3 substituents are substituted by 6 to 18 carbon atoms, such as trinonylphenyl, dodecylphenyl or triphenyl phosphate. These inhibitors are usually used in amounts of 0.01 to 0.6% by weight, based on the dicarboxylic acid component used.

To achieve an even higher molecular weight, the polyalkylene terephthalates can be a solid polycondensation subject. Usually the granulated product is used

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in a stream of nitrogen or in a vacuum at a pressure below 1 Torr and a temperature that is 60 - 6 ° C below the polymer melting point, polycondensed in the solid phase,

The preparation of the phthalic acid ester b) can be carried out by esterification or transesterification of phthalic acid, its anhydride and / or its Dialkyl esters, preferably methyl esters, take place with monohydric or monohydric and dihydric alcohols. A detailed description of the various manufacturing methods can be found at E. Müller, Methods of Organic Chemistry (Houben-Weyl), Vol. 14/2, pp. 1 f., Georg Thlerne Verlag, Stuttgart 1963, and at V.V. Korshak and S.V. Vinogradova, polyester, Pergamon Press, Oxford 1965, pp. 34-63.

Examples of suitable phthalic acid esters b) are: Di-isopropyl phthalate, Di-tert-butyl phthalate, Di-2-ethylhexyl phthalate, Di-isononyl phthalate, Di-isononyl-poly-tri-ethylene glycol phthalate.

The mixture of polyalkylene terephthalate a) and phthalic acid ester b) can be prepared on commercially available mixing devices be performed. Kneaders, single-screw and twin-screw extruders are suitable as such. For further processing can the mixture obtained can be granulated after the melt has solidified. Solid-phase post-condensation can also follow here.

To protect against thermo-oxidative degradation, the thermoplastic compositions according to the invention can be in the usual amounts, preferably from 0.001 to 0.5% by weight, based on the unfilled and unreinforced polyalkylene terephthalates, stabilizers added

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are set. Suitable as such are, for example, phenols and phenol derivatives, preferably sterically hindered phenols which contain alkyl substituents with 1-6 carbon atoms in both o-positions to the phenolic hydroxyl group, amines, preferably secondary arylamines and their derivatives, phosphates and phosphites, preferably their aryl derivatives, Quinones, copper salts of organic acids, addition compounds of copper (I) halides to phosphites, such as 4,4'-bis (2,6-di-tert-butylphenol), 1,3,5-trimethyl-2, 4,6-tris- (3,5-di-tert-butyl-4-hydroxy-benzyl) benzene, 4,4'-butylidene-bis (6-tert-butylm-cresol), 3.5 -Di-tert-butyl-4-hydroxy-benzyl-phosphonic acid diethyl ester, N, N'-bis- (ß-naphthyl) -p-pha ^ lendianiin, N, N'-bis- (1-methylhepty1) -p- phenylenediamine, pheny1-ß-naphthalamine, 4,4'-BIs - (^., <L ·, -dimethylbenzy1) -diphenylamine, 1,3,5-tris- (3,5-di-tert-butyl-4 -hydroxy-hydrocinnamoyl) -hexahydro-s-triazine, hydroquinone, p-benzoquinone, tolu-hydroquinone, p-tert.-butylbenzcatechol, chloranil, naphthoquinone, copper naphthenate, copper octoate, Cu (I) Cl / triphenyl phosphate, CÜ (I) Cl / trimethyl phosphite, Cu (I) Cl / trischloroethyl phosphite, Cu (I) Cl / tripropyl phosphite, p-nitrosodimethylaniline.

The thermoplastic compositions according to the invention can be reinforced with reinforcing materials. As reinforcing materials Metals, silicates, carbon, glass, primarily in the form of fibers, fabrics or mats, have proven their worth. Glass fibers are the preferred reinforcing material.

In addition, if desired, inorganic or organic pigments, dyes, lubricants and release agents such as Zinc stearate, montan waxes, UV absorbers, etc. are added in the usual amounts.

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To obtain flame-retardant products, 2 to 20% by weight, based on the thermal mass, flame retardants known per se, e.g. halogen-containing compounds, more elementary Phosphorus or phosphorus compounds, phosphorus-nitrogen compounds, antimony trioxide or mixtures of these substances, preferably antimony trioxide, decabromobiphenyl ether and tetrabromobisphenol A polycarbonate are added.

The rate of crystallization of the polyester injection molding compositions according to the invention can be increased by adding from 0.01 to 1 % By weight, based on the unfilled and unreinforced polyester, nucleating agents can be increased. as such are the compounds known to the person skilled in the art, such as those in the Kunststoff-Handbuch, Volume VIII, "Polyester", Carl Hanser Verlag, Munich, 1973, page 701, are described.

The polyester compositions according to the invention are excellent starting materials for the production of moldings of all kinds by injection molding.

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Examples

To determine the achievable processing cycle time the injection mold of a gear wheel (0 40 mm) was used, in which the injection molded part by four ejector pins from the Shape was pressed. The injection cycle was determined in which the ejector pins are just no longer in the finished molding penetrated and the molding fell out of the mold without difficulty.

Table 1 gives the mold stand and total injection cycle times of some polyester compositions according to the invention on the basis Polyethylene terephthalate and phthalic acid ester (Example 1,2) in comparison with the unmodified polyethylene terephthalate at. Comparative Examples 3-4 show the processing behavior of polyethylene terephthalate blends with Phthalic acid esters that contain linear aliphatic alcohols as end groups. These polyester compositions can In comparison to pure polyethylene terephthalate, sprayed to form fully crystalline products at a lower mold temperature will. However, it is not possible to shorten the mold or cycle time.

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Table 1

Example phthalic acid ester cylinder mold temperature mold life total injection molding-2 type quantity temperature cycle

(% By weight) ( ⁰ C) ( ⁰ C) (sec.) (Sec.)

1 di-isoronyl-5 260 107 10 19.5 phthalate

2 di-isawnyl- 5 260 110 7 16.5 <x> poly-tri-

o ethylene glycol

co colphthalate

oo

(Λ 1 diethyl 5 260 111 40 49.5

> ~ phthalate

Of 4 di-butyl-5 260 112 35 44.5

co phthalate

οι

5 270 140 30 39.5

Tabel

oo processing behavior ναι polyester compositions based on copolyethylene terephthalate (0.6 mol% 2-ethylhexane ^w diol-1,3) and phthalic acid ester

Example phthalic acid ester Cylinder fan temperature Mold life Type amount temperature

(% By weight) ( ⁰ C) ( ⁰ C) (sec.)

Total injection molding cycle (sec.)

Di-iscnyl phthalate

Di-isononyl poly-triethylene glycol phthalate

260

260

110

108 14.5 12.5

270

130

10 19.5

Claims (3)

Claims a) 70-99.5% by weight of a high molecular weight polyalkylene terephthalate with an intrinsic viscosity of at least 0.6 dl / g (measured as a 0.5% by weight solution in a phenol / tetrachloroethane mixture in a weight ratio of 1: 1 at 25 ° C) and b) 0.5-30% by weight of a phthalic acid ester with a medium Molecular weight from 200 to 2000 of the formula O O 2 1 "" R - (0R ^J -) _n C R is a branched aliphatic radical with 1-12 C atoms, 3 R, R is a linear or branched aliphatic radical with 1-12 carbon atoms, η 0 or an integer from 1 to 4 and χ 0 or an integer from 1 to 15 are. 2. A method for producing the masses according to claim 1, characterized characterized in that 70-99.5% by weight of a high molecular weight polyalkylene terephthalate with an intrinsic viscosity of at least 0.6 dl / g (measured as 0.5% by weight Solution in a phenol / tetrachloroethane mixture in a weight ratio of 1: 1 at 25 ° C) and 0.5-30% by weight of a phthalic acid ester of the above constitution and mixed in the melt homogenized. Le A 17 835 - 16 - 8 · <ύ »33/0385 »... '·>' · ■ * ■ * '■' '■■' ■ ORIGINAL INSPECTED 3. Use of phthalic acid esters of those indicated above Constitution to increase the crystallization and the rate of crystallization of polyalkylene terephthala th. 80983